Process for the manufacture of mono-benzoyl-diamino-anthraquinone compounds



Patented Feb. '21, 1928.

'rER, ENGLAND, MANCHESTER; ENGLAND.

COMPOUNDS.

PROCESS FOR THE UFACTURE OF MONO-BENZOYL-DIAMINO-ANTHRAQUINON benzoyl derivatives.

amino-anthraquinones able intermediates in i I No Drawing. Application filed March 4, 1926, Serial No. 92,382, and in Great Britain July 8, 1925.

This invention relates to the ma ufacture mono-benzoyl derivatives of diamino-anraquinones including substituted mono- Monobenzoylated dihave long been valuthe manufacture of dyestufl's of the anthraquinone series but no simple way of known. I

preparing them has been a diamino-anthraqulnone be treated with benzoyl chloride both amino groups are attacked so that if benzoylation r0 th th and ours at all the dibenzoyl derivative is the In some casesthe following ute has been successfully used for getting e desired products. The mono-amino-anraquinone is acetylated and then nitrated saponified and the nitro-amino-anthraguinone is then benzoylated and converted in to the mono-benzoy'l-diamino-anthraquinone by reduction.

An attempt has been made to obtain the desired mono-benz oylated derivatives from diamino-anthraquinones by first treating the di'amino-anthraquinone with oxalic acid to obtain the ca di th withoutmono-oxamino derivative. These n then be benzoylated to benzoyl-oxalylamino-anthraquinones and it was hoped at the oxamino group could be removed interfering with the benzoyl group,

but in practice this process often fails owing the conversion of the oxalyl group into a formyl group which resists removal except by processes which also eliminate the henzoyl group.

We have now found that mono-benzoyl? and substituted monobenzoyl-diamino-anand obtained very simply raquinones can be treating the diaminoin good yield by anthraquinones with benzoic anhydride or a substituted benzoic 'anhydride.

The reaction is preferably effected in the presence of solvent and nitro-benzene appears to be e most convenient to use. The benzoic slight excess over the for producing the mononzoyl derivative.

The following examples will. servefur er to illustrate thenature of the invention,

benzoyl derivative. -derivative can be hydrolyzed and the diamative and with but the invention is not confined to the examples. The parts are by weight.

100 parts of 1:5-diamino-anthraquinone are well stirred in 1000 parts of nitrobenzene at l75l80 C.v for halfan hour. 110 partsbenzoic anhydride (15.8% over theory for one benzoyl group) dissolved in 100 parts of nitrobenzene by warming on the water-bath are then added to the solution of diaminoanthraquinone and the whole well stirred at 175 C. for to minutes. The reaction mixture is cooled to 120 C. and filtered. The residue is the dibenzoyl compound. The filtrate is allowed to stand for 1 ,4 to 2 hours, or until its temperature reaches 30 derivative crystallizes out and tilteredofi', washed with spirit and dried. V hen working as above described about 98 parts of the desired monobenzoyl-aminoanthraquinone are obtained and about 31 parts of the di- If desired the dibenzoyl ino-anthraquinone recovered and used in a subsequent operation. A further recovery of the diaminoanthraquinone can be effected by distilling off the nitrobenzene, finishing the distillation in steam and hydrolyzing the residue.

The amout of varied but if a smaller yield is less and the quality of the product inferior. If the amount of benzoic anhydride be increased say to excess less anhydride used can be .monobenzoyl" compound is obtained and more dibenzoyl. Similarly also variations can be made-in the amount or'quantity of the solvent but higher concentrations appear to favour the formation of dibenzoyl derivthose described in the example, although the weight of monobenzoyl body obtained appeared to be increased, the purity of the product suflers.

If desired the 'benzoylation can be carried C. when the monobenzoyl quantity be used the r lower concentrations than I out with benzoic anhydride made in the presence of the diamino-anthraquinone, for instance, from benzoyl chloride and benzoic acid or sodium benzoate instead of taking separately prepared benzoic anhydride, but we have obtained the most satisfactory results by using isolated benzoic anhydride as described in the foregoing example.

The 1 amino-S-benzoyl aminoanthraquinone can be prepared in the same way but in this case the yield of the dibenzoyl compound is smaller. Also the l-aminoi benzoyl-amino-anthraquinone can be prepared similarly but in this case no dibenzoyl derivative appears to be formed even when a 30% excess of benzoic anhydride is used.

anthraquinones but it is also valuable as Example II..-Preparati0n of 1-vam2'n0-5- am'soyl-aminoanthmguinone.

By treating 1: 5-diaminoanthraquinone with anisic anhydride in the manner described above, the rnonoanisoyl-l-5-diaminoanthraquinone is obtained. 130 parts of ani sic anhydride are required for 100 parts of the diamine. The reaction mixture is filtered at 110-120 G, the residue being the dianisoyl derivative. The filtered liquors on standing deposit the monoanisoyl compound which is filtered off at 40-50 C. About 88 parts are obtained which after one recrystallization from nitrobenzene shew a melting point of 232-233 C.

This process not merely affords a simple Way of preparing the monobenzoyl-aminoreeocee affording a simple means of protecting one amino group of a diamino-anthraquinone. This can already be done by the aid of oxalic acid forming the amino-oxamino compounds but the mono-benzoyl compounds offer distinct advantages in many cases.

We claim 1. The process .of preparing monobenzoyldiamino-anthraquinones which comprises treating diamino-anthraquinones with a benzoic anhydride in the presence of a solvent.

'2. The process of preparin monobenzoyldiamino-anthraquinones which comprises treatin diamino-anthraquinones with a benzoic an iydride in the presence of a solvent comprising nitrobenzene.

3. The process of preparing substituted monobenzoyl-diamino-anthraquinones which comprises treating diamino-anthraquinones with a substituted benzo1c anhydride in the presence of a solvent comprising nitrobenzene.

4:. The process of preparing monobenzoyldiamino-anthraquinones which comprises treating a diamino-anthraquinone with a benzoic anhydride, the anhydride being in slight excess over the theoretical amount necessary to form a monobenzoyl-diaminoanthraquinone, and the process being carried out in the presence of nitrobenzene as a solvent.

In testimony whereof we have hereunto afiixed our signatures.

WILLIAM HENRY PERKIN. HUGH hmJLS BUNBURY. 

